1. Field of the Invention
The present invention relates to a bone implant, preferably a bone implant for implanting prosthetic pieces in a bone, such as dental prosthesis in a bone, the implant comprising a fixing piece or body to be affixed in a bone and a mounting intermediate member for receiving the prosthesis piece, the mounting member being capable of being removed without traumatic effects for the patient in the event that the prosthesis or a fixing stud thereof is broken. The intermediate member can be removed even after a long time with the fixing body already integrated into the bone. Of course, the concepts of the invention are easily applied to any implant piece that must be implanted in a human being or animal bone. In addition, the invention is not only applied to expandable implants, of the type that can be initially expanded to get a retention into the bone, but also to non-expandable implants. According to the invention the implant, if of the expandable type, comprises, in combination with the intermediate member, an expanding assembly which may be operated through the intermediate member for the intermediate member for installation purposes but the intermediate member may be disengaged from the expanding assembly in order to be removed from the implant.
2. Description of the Prior Art
It is well known in medical art to provide bone implants that are useful for affixing a prosthetic piece in a bone, in replacement of any lacking natural piece or member or for joining parts of one or more bones. More, particularly, these implants are well known in the odontology wherein dental implants are used for replacing a dental piece that has been lost or extracted either in a human or animal patient. One of the problems or traumatic drawbacks of implanting a dental prosthesis in a patient is that a long time is necessary to assure to the patient that the implant is entirely or totally integrated to the bone of the patient. Generally, after the extraction or loosening of the dental piece, a fixing body of the implant is inserted and implanted into the bone and several months must pass to determine whether the fixing body has been integrated to the bone or bone fibers of the bore in the bone, this determination being necessary to continue or not with the next step of affixing the prosthetic piece into the implant. If the body has not been integrated the same must be replaced and a new waiting period begins again. This provokes anxiety and affliction in the patient who must await for months before receiving a positive diagnosis from the odontologist or the implantologist and upon a negative diagnosis the patient knows that the fixing body must be removed and that several additional months must pass. With the purpose of shortening these waiting periods, some implants, either of the expandable or non-expandable type have been developed. The expandable increased bone growth is generated. These implants are installed within the bone orifice or bore resulting from the loosened or removed dental piece or within a bore made in the bone, and the implant is radially expanded in order to get a positive initial pressure and retention. During the first weeks after the installation, it is possible to verify whether micro-mobility exists and, if the micro-mobility is detected, the implant is additionally expanded to improve the radial retention. The purpose of these additional expansions is to obtain immobility of the fixing piece that is fundamental for obtaining the integration of the piece into the bone. While these implants have been improved insofar as to the micro mobility is concerned, the same have not taken into account an important aspect of the implants, that is the need of replacing a broken prosthesis after a long elapsed time from the integration of the implant into the bone. Another aspect not taken into account by the prior art is that the expanding means used for expanding the expandable implants must be easy and safe to operate without complex and excessive friction mechanisms.
Generally, prosthetic dental pieces are affixed to a fixation stud or abutment that is installed by threading or adhesive within the fixing or mounting body that is already integrated into the bone. During the use of the prosthetic piece, if the fixing stud is broken within the fixing body that is already integrated or implanted, the broken portion of the stud that remains within the implanted body must be removed before a new prosthetic piece is re-installed. Any professional skilled in the art knows that the removal of this broken stud in the small room of the patient""s mouth is very difficult if not impossible. Said broken portion is not accessible and very frequently the portion cannot be extracted, therefore the implant body must be removed from its implantation by drilling the patient""s bone to release the fixing body from the bone, what is very traumatic for the patient.
The initial fixation of the implant has been treated by several professionals and disclosed in many documents like U.S. Pat. Nos. 5,004,421 and 5,087,199 to Lazarof, which disclose expandable implants having a fixing piece that is introduced and threaded into a patient""s bone and has a hollow interior that is also threaded and a plurality of longitudinal cuts in the implant body. An expanding piece is arranged within the hollow interior, the piece being acceded from a top end of the fixing body by means of a tool that is introduced within the implant body to cause the expanding piece to rotate and move upwardly in order to expand the implant body to enhance the retention thereof into the bone. An upper portion of the fixation body has a threaded inner orifice for receiving a fixing stud or abutment of the dental prosthesis. While a better initial fixation is achieved, no consideration is made to the event that the prosthesis stud is broken and the prosthesis is loosened.
U.S. Pat. No. 5,489,210 discloses a dental implant having a fixation body that is introduced within the body and has a plurality of longitudinal cuts at a lower end of the body, this lower end being expanded by an expanding piece that is introduced through an upper end into the implant body and exerts a pressure against the lower end of the body to outwardly radially expand the same against the bone. Again, the initial pressure of the implant against the bone is improved but a solution to the event of a broken stud is neither disclosed nor suggested. The stud of the prosthetic piece is mounted directly within the fixing body of the implant.
U.S. Pat. No. 5,611,688 discloses an expandable dental implant also comprising a hollow tubular outer body that is affixed by expansion into the bone, the expansion being obtained by an expanding screw that is inserted into the hollow body and the initial fixation of the implant is improved. This patent does not disclose any solution to the event that the prosthesis and its fixing stud is loosened or broken. In like manner, U.S. Pat. No. 5,931,674 discloses an expandable implant very similar to Patent ""688 but no means for permitting an easy removal of a broken fixing stud are provided neither the problem is addressed.
U.S. Pat. No. 3,708,883 to Flander discloses a dental implant having an elongated tubular body of the expandable type with an elongated spreader screw extending through the tubular body and a wedge-shaped spreader at a distal end of the screw, the screw being actuated by pulling means in the form of a nut which is turned to pull the spreader means beyond the nut and expand the body. Spreader threaded stem is moved upwardly and projects out from the body thus forming an obstacle for any mounting work necessary at a proximal end of the body when installing the dental prosthesis.
U.S. Pat. No. 5,209,753 to Biedermann discloses a bone screw with a shaft having threaded portions at a bottom and a top of the shaft, with a tip fixed at the bottom of the shaft to expand the bone screw when the shaft is rotated within the bone screw. First, the shaft must be rotated to be fixed to the tip and then the shaft must be unscrewed in order that the expander part be pulled into the bone screw to expand the bone screw. This is a very complex operation and an unsafe fixing and installation of the bone screw may be obtained.
U.S. Pat. No. 6,142,782 to Lazarof discloses an implant assembly comprising an elongated hollow body with an internal shoulder and a draw screw having a head captured within the hollow body and engaging the internal shoulder to form a seal with the body. While the expansion of the body is achieved by this system, no solutions are provided to the event the abutment is broken and the fixation part of the abutment remains retained within the hollow body. In addition, for installing the draw screw a screwdriver or allen wrench must be introduced into the hollow body with the inconveniencies this cause to the implantologist who must accede to the screw head without a view of same.
It would be therefore convenient to have a new expandable or non expandable implant provided with means for enhancing the initial fixation of the implant within the bone, and means for permitting the easy removal of the fixation stud of the prosthesis piece in the event the stud is broken, with a portion of the stud remaining within an implant body already integrated to the bone.
It is therefore one object of the present invention to provide a bone implant for fixing a dental prosthesis into a bone, the prosthesis being fixed into an implant body by means of a fixing stud that is fixed into the body, in the event the stud is broken and the prosthesis is loosened, the novel implant permitting the easy removal of a portion of the stud that remains within the body without the need of removing the body from the bone, the implant also comprising, alone or in combination with the intermediate member, an expanding assembly.
It is still another object of the present invention to provide a bone implant comprising a fixing tubular body for fixing in the bone, the tubular body including a distal end for being affixed within a bone bore and a proximal end for remaining accessible outside the bone and a prosthesis piece being received in the proximal end, the bone implant comprising a mounting intermediate member for mounting said prosthesis piece, the intermediate member being removably mounted within said tubular body, the intermediate member including a proximal end in communication with an inner surface for receiving a fixing stud of said prosthesis piece.
It is a further object of the present invention to provide a bone implant comprising a fixing tubular body for fixing in the bone, the tubular body including a distal end for being affixed within a bone bore and a proximal end for remaining accessible outside the bone and within the gum and for receiving a prosthesis piece, the distal end of the body including a plurality of longitudinal cuts that permit a lower portion of the body to be radially outwardly expanded by an expanding member that is received within said body, said expanding member being fixed to a distal end of a stem having a proximal end within said tubular body and a threaded outer surface, the implant also comprising a rotatable mounting intermediate member that includes a threaded inner surface within which said stem is threadably received, the mounting intermediate member including an upper end receiving the prosthesis piece.
It is still another object of the invention to provide bone implant comprising a fixing tubular body for fixing in the bone, the tubular body including a distal end for being affixed within a bone bore and a proximal end for remaining accessible outside the bone and a prosthesis piece being received in the proximal end, the bone implant comprising a mounting intermediate member for mounting said prosthesis piece, the intermediate member having an at least partially threaded outer surface for threadably connecting an at least partially threaded bore in the body, the intermediate member including an inner surface for mounting said prosthesis piece.
It is even another object of the invention to provide an expandable bone implant comprising an elongated hollow body for fixing in the bone, the tubular body including an expandable distal end for being affixed within a bone bore and a proximal end for remaining accessible outside the bone and for receiving a prosthesis piece, the bone implant comprising a bore extending along the length of the hollow body, the bore having a first proximal bore portion and a second distal bore portion, a mounting intermediate member for mounting said prosthesis piece, the intermediate member being removably mounted within the proximal bore portion of the hollow body, the intermediate member including an inner surface for mounting said prosthesis piece, and an expanding assembly comprising a screw having a proximal end and a distal end, with an expanding member threaded onto said distal end, the proximal end of the screw being removably connectable to the intermediate member in a manner that when the intermediate member is rotated in a first sense of rotation the screw is rotated in said first sense of rotation for moving the nut along the screw to expand the distal end of the body outwardly.
It is another object of the invention to provide an expandable bone implant comprising an elongated hollow body for fixing in the bone, the tubular body including an expandable distal end for being affixed within a bone bore and a proximal end for remaining accessible outside the bone and for receiving a prosthesis piece, the bone implant comprising a bore extending along the length of the hollow body, the bore having a first proximal bore portion and a second distal bore portion, a mounting intermediate member for mounting said prosthesis piece, the intermediate member being removably mounted within the proximal bore portion of the hollow body, the intermediate member including an inner surface for mounting said prosthesis piece, and an expanding assembly comprising a screw having a proximal end threaded into said intermediate member and a distal end including an expanding member, the proximal end of the screw being removably connectable to the intermediate member in a manner that when the intermediate member is rotated the screw is rotated and moved upwardly into the hollow body whereby the expanding member expands the distal end of the body outwardly, the screw including a radially extending plate forming a seal against an inner surface of the bore of the hollow body.
The above and other objects, features and advantages of this invention will be better understood when taken in connection with the accompanying drawings and description.